Plasticized poltvinyl acetal



Patented Mar. 13, 1945 UNITED STATES PATENT OFFICE rms'rrorznn POLYVINYLAcnrAL ooMrosrnoN I Elmer 8. Derby, Springfield, Mass., assignor toMonsanto Chemical-Company, St. Louis, Mo., a

corporation of Delaware No Drawing. Application October 23, 1941, SerialNo. 416,152

- 4 Claims.

the necessary physical properties to fulfill thecommercial and technicalrequirements. A satisfactory laminated glass must give satisfactorybreak tests, both hot and cold, this term being used in the ordinarysignificance with which it is employed in the trade. The plasticinterleaf material must have satisfactory light and water resistance;stability, 1. e., resistance tochange by reason of age; clarity;color;'adhesion to glass; and satisfactory hardness at the temperatureof use. Perhaps the most satisfactory base material at the present timeis a partial polyvinyl acetal resin, i. e., a material made bycondensing an aldehyde with a hydrolized polyvinyl ester, such a resinbeing described in the patent to Morrison et al., Reissue No. 20,430,dated June 29, 1937. These resins are conveniently called polyvinylacetal resins. These resins vary in the degree of hydrolysis of theester and the degree of combination of the aldehyde.

For instance, the-molecules of a satisfactory resin made withformaldehyde may be considered to.

The resins,

of the final product to adhere to glass. The properties of the finalproduct can be regulated by varying the proportions of the threecomponents in the resin, and this can be accomplished in the course ofmanufacture of the resin.

However, as is well known to those skilled in the art, the properties ofplastic material for ,laminated glass made from partial polyvinyl acetalresin as a base, depend, on the character and amount of the plasticizeremployed about as much'as on the resin itself, and the utilization ofthese resins has been seriously retarded by the extreme dimculty ofdiscovering a suitable plasticizer which for a particular resin, whenused in the necessary amounts, will give to the final productttheoptimum qualities. These plasticizers are usually heavy esters, i. e.the esterification products of the glycols,.polyglycols, monobasicalcohols and glycerolwith monobasic aliphatic acids, phthalates ordibasic aliphatic acids, tribasic acids, or phosphoric acid; but not allsuch substances can be used with the resins in question, or,insufiicient quantities to produce appreciable or satisfactory results.Accordingly it has been necessary to do a large amount of experimentalwork to determine what plasticizer to use and the amount which with anygiven resin will produce the best plastic for laminated glass. I

I have discovered that of a chemical series of plasticizers that onewill give the best results which in the proportion necessary for goodbreak tests is that one in the series of materials which is below butclose to the point of incompatibility with the particular resin and yetis capable of permanent-miscibility with it. I believe that in generalthe plasticizer which is next below the amount used. The eflect of theacetate in the character of the aldehyde employed in the formation ofthe acetal. It has also been suggested that the hydroxyl groupsincrease" the capacity point of incompatibility will be best; but 1 findthat in certain cases those which are immediately below in the seriesgive usable but decreasingly good results. Therefore to determine whichplasticizer of a given series shall be used it is well will be "foundthat a mixture in the same proportions made with this phthalate can beused' and that it will give the. best physical properties in ;theplastic.

ompa ility makes 39 parts.

itself manifest in the form of slight exudation after standing, thesurface becoming oily or greasy, and in the appearance of haze due tothe collection of tiny masses of the plasticizer which interfere withthe transmission of light.

It is further found that certain plasticizers may be used. in largeamounts without segregation and certain others in small amounts. Theplasticizer to be chosen should be one which can be mixed in asufficient quantity tohave an appreciable effect on the final product.The amount ofplasticizer to be used can be determined from the resultsof break tests, on laminated glass made with the particular plastics. inquestion. A convenient method is to make up several batches ofthe'material with increasing percentages of plasticizer, then make bothhot and cold break tests of about 82% of acetal, 8% of hydroxyl groupscalculated as polyvinyl alcohol and 10% acetate,

the following plasticizers and amounts give the best results.

'(1) Diethyl phthalata-The range is 90 to 110 parts of diethyl phthalateto 100 parts of the resin and the preferred amount is 100 parts ofdiethyl phthalate.

v (2) Diethylene glycol dipropionate.-The range range is from 65 to 185parts and thepreferred and plot the results against the percentage ofplasticizer to resin. The, curve of the hot break test will usually befound'to drop off rapidly as the amount of plasticizer is increased,while the curve'of the cold break test will be found to rise sharplywith the increase in plasticizer up to a certain point and then will'drop, sharply again. If an amount of plasticizer is' employed whichcorresponds closely to the point where the two curves first cross eachother, it will be found that the material thus produced has the bestcombination of physical properties for the purpose intended. v a

I have discovered that with certain resins now available the bestresults may be obtained as follows: I Polyvinyl ,acetal resin made withbutyraldehyde vinyl alcohol, 0 to 2% acetate, and the balance acetal,the following plasticizers in the amounts specified give the bestresults;

(1) Dz'butyl digZycollate.-Satisfactory results may be obtained withfrom to 50 parts of dibutyl diglycollate to 100 parts of the resin, butthe best results are obtained when about 38 parts are employed.

(2) Triethylene glycol dzbutyrate.-The range of satisfactory results isfrom 30 to 50 parts of the plasticizer to 100 parts of the resin. Thebest results are obtained with 40 parts.

(3) Tributyl.phosphate.-The range is from 25 to 45 parts and the bestresults are stantial equivalent of dibutyl diglycollate, both'are'intended to be included in the appended claims wherever eitherappears. 1 l

(9) Ethyl laurata- -Th'e range is from 45 to 65' parts and thepreferred. amount 55 parts.

(10) .Di-ethoxy-ethyl phthalate.-The range is from 70 to 90 parts andthe preferred amount 80 parts.

Polyvinyl acetal made. with formaldehyde For resins of this characterhaving proportions amount 75 parts.-

(5) Di-ethyl succinate.-The range is from 40 to 60 parts and thepreferred amount 50 parts.

' (6) Di-methyl sebacqta-The range is from 40 to 60 parts and thepreferredamount 50 parts. Although the substances specifically mentionedabove are especially suitable for the particular purpose describedabove, for the purpose of modifying, and particularly plasticizing,polyvinyl acetal resins, aliphatic monobasic acid esters of ethers ofpolyhydric alcohols; and especially aliphatic monobasic acid esters ofmono-alkyl ethers glycols, which esters have from about 11 to about 13carbon atoms, and aliphatic monobasic acid esters of mono-aromaticethers of glycols.

Examples of aliphaticmonobasic acid esters oi mono-alkyl ethers ofglycols comprehended by this. invention are butyl ether of diethyleneglycol mono-'buty'rate (butoxy-ethoxy-ethyl butyrate), butyl ether ofdiethylene glycol mono-propionate, propyl ether of ethylene-propyleneglycol monobutyrate (propoxy-ethoxy-propyl butyrate) butyl 40 ether ofdiethylene glycol mono-valerate, ethyl obtained with ether oftriethylene glycol mono-butyrate, amyl ether of ethylene glycolmon0--butyrate,; and hexyl etherof ethylene glycol mono-lactate. Of thealiphatic monobasic acid esters of monoalkyl ethers of glycols mentionedabove, the saturated fatty acid esters of the mono-lower alkyl ethers ofglycols, which esters have from about 11 to about 13 carbon atoms, suchas butyl ether of diethylene glycol mono-butyrate, are preferred,especially for plasticizing a polyvinyl acetal resin made withbutyraldehyde.

V Examples of aliphatic monobasic acid esters of mono-aromatic ethers ofglycols comprehended bythis invention are benzyl ether of diethyleneglycol mono-propionate (benzoxy-ethoxy-ethyl propionate), naphthyl etherof ethylene glycol mono-acetate, phenyl ether of diethylene glycolmono-butyrate,

phenyl ether of triethylene glycol mono-acetate, tolyl ether of ethyleneglycol mono-lactate, phenyl ethyl ether oi. di-ethylene glycolmonopropionate, and xenyl ether of diethylene glycol mono-acetate. Ofthe aliphatic monobasic acid esters of aromatic ethers of glyether ofdiethylene glycol cols, the saturated fatty acid esters of monoaromatichydrocarbon ethers of glycols, said nucleus and from esters having asingle benzene about '10 to about 20 carbon atoms, such as benzylmono-propionate, are preferred, especially for a polyvinyl acetal resinmade with'formaldehyde or butyraldehyde.

This application is a continuation-in-part of my co-pending applicationSerial Number 172,443,

filed November 2, 1937.

What isclaimed is: 1. A plastic composition or matter comprising thisinvention embraces, I

' a. polyvinyl acetal resin and, as a. modifying agent therefor, benzylether of diethylene glycol monopropionete.

2. A plastic composition of matter comprising a, polyvinyl formaldehydeacetal-resin and, as a modifying agent therefor, benzyl ether ofdiethylene glycol mono-propionate.

3. A plastic composition of matter comprising a polyvinyl formaldehydeacetal resin and from substantially 65 parts to substantially 85 partsbenzyl ether of diethylene glycol mcno=propionote for each 100 parts ofresin.

4. A plastic composition of matter comprising a, polyvinyl butyreldehyde acetal resin and. as a modifier therefor, benwl ether of diethyleneglycol monopropionate.

